Lubricating oil composition



United States Patent 2,997,442 LUBRICATING 01L COMPOSITION Louise F. Peale, Philadelphia, and Joseph F. Messlna, Havertown, -Pa., assignors to the United; States of America as represented by the Secretary of the Army No Drawing. Filed Mar. 30, 1960, Ser. No. 18,778

I v 3 Claims. (Cl. 252-493) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein maybe manufactured and used by or for the Government for governmental 2,997,442 Patented Aug. 22, 1961 ice were intimately blended with bis (2-ethylhexyl) sebacate oil and then subjected to extreme pressure and anti-wear purposes without the payment to us of anyroyalty compositions of this type having improved extreme pressure and anti-wear characteristics.

Requirements upon lubricants by developments in mechanical design are rigid and drastic. In many instances pressures at bearing surfaces are higher than those which synthetic oils will normally withstand. Illustrative are the conditions encountered, for example, in applications where high unit pressures are involved. In many machines, operation is, at least in part, under conditions of thin film lubrication or under similar conditions where film strength and anti-wear characteristics of high order are required of the lubricating medium.

While it is generally true that a few commercial addition agents will improve the extreme pressure and antiwear characteristics of the synthetic lubricating oil, the additives of the present invention are comparable with, and in one instance, is far superior to the commercial additives. In many instances, however, these addition agents are deficient in imparting anti-wear properties thereto.

It is therefore, a principal object of this invention to provide a compounded lubricating product of synthetic base oil possessing extreme pressure and anti-wear charaoteristics of a high order.

It is another object of the invention to provide a lubricant having improved extreme pressure and anti-wear properties, said lubricant comprising a major proportion of an oil of synthetic origin having a long chain phosphorus derivative of a fatty acid blended therewith.

Other objects and features of the invention will become apparent as the invention is more fully hereinafter disc osed.

In accordance with these objects it has been discovered that minor additions of selected long chain phosphorus derivatives of fatty acids to bis(Z-ethylhexyl) sebacate are characterized by good extreme pressure and anti-wear properties. More specifically, it has been found that dibutyl lauroxyethylphosphonate, di(2-ethylhexyl) lauroxyethyl-phosphonate and diethyl oleoxybutyl phosphate are capable of imparting these desirable properties to the bis(2-ethylhexyl) sebacate. The lubricity agents of the present invention are made by conventional methods and will not be described.

1 through 6 weight percentages of each of dibutyl di(2-ethylhexyl) lauroxyethylphosphonate.

evaluation tests. These tests were conducted on conventional laboratory equipment and will not be described in detail, as their operations are well known to those skilled in the art. For example, anti-wear data were obtained on the Shell 4-ball wear tester while extreme pressure data were determined using the well-known Falex and Shell 4-ball extreme pressure tester. Description of the Shell 4-ball testers may be found in an article by G. D. Boerlage, Engineering, vol. 136 (1933), p. 46 et seq. The Falex extreme pressure tester is described in Lubrication Engineering, September 1946, V. A. Ryan.

The tabulated comparative data following illustrates the extreme pressure and anti-wear effectiveness of the present invention when incorporated in a synthetic lubricating oil such as bis(Z-ethythexyl) sebacate:

Shell Falex Shell 4-Ball Wt. 4-Ball Extreme Extreme Pres- Per- Wear Pressure sure Additive cent Scar I aw Addl- Diam- Load at tlve eter Failure Seizure Weld (mm) (1bs.) Load Load N one 859 1, 000 50 100 Dlbutyl lauroxyethylphosphonate 2 562 1, 760 60 180 Do 5 559 1, 750 180 Dl(2 ethylhexyl)lauroxyethylphosphonate. 2 546 3, 250 180 D0 5 550 3, 250 90 Dlethyl oleoxybutyl phosphate 2 795 2, 250 130 Do a 588 2, 250 120 Commercial tricresyl phosphate 2 433 l, 250 60 140 Do l5 401 1, 250 80 140 Commercial triisopropyl phosphlte 5 530 1, 750 80 140 D0 2 670 1, 500 80 140 l Seizure may be defined as the load at which a significant increase in wear scar diameter takes place.

b Weld may be defined as the load at which the balls fuse together.

The commercial tricresyl phosphate imparts excellent anti-wear properties to bis(2-ethylhexy1) sebacate, as shown in the above table, but is of little benefit in improving its extreme pressure characteristics. Commercial triisopropyl phosphite is presently used as a lubricity agent in diester lubricating oils such as bis(Z-ethylhexyl) sebacate. The tabulated data show the dibutyl lauroxyethylphosphonate and diethyl oleoxybutyl phosphate to be comparable to the commercial triisopropyl phosphate. The di(2-ethylhexyl) lauroxyethylphosphonate, while equally satisfactory to the commercial triisopropyl phosphite in anti-wear properties, is far superior however in providing extreme pressure characteristics to the his 2- (ethylhexyl) sebacate.

All values presented in the table are averages of five different measurements. Maximum variance among the five values was confined to within a 10% range. Although 2 and 5 weight percentages of the lubricity additives of the invention are presented only, it should be understood that intermediate additions were found equally satisfactory, that is, between 2 and 5 weight percentages.

From the data hereinabove set forth, it will become apparent that the lubricity additives of the present invention, when confined within the prescribed range of about 2 to 5 weight percentages improve both extreme pressure and anti-wear characteristics of the synthetic base oil.

Amounts of the respective lubricity additives below about 2% by weight do not produce sufiicient advantageous efiect to render the composite oil lubricant adequate for extreme pressure and anti-wear "use. Similarly, if the additive is incorporated with the bis(2-ethylhexyl) sebacate in quantities greater than about 5%, the composite lubricant shows no further improvement in the level of these properties, and, in several instances, a slight decrease in levels results.

We claim: 7 1. A lubricant composition having good extreme pressure and anti-wear properties suitable for use in systems wherein high unit pressures are involved, said lubricant consisting essentially of about 2 to 5 weight percent of dibutyl lauroxyethylphosphonate and the balance being his 2-ethylhexyl) sebacate.

2. .A lubricant composition having good extreme pressure and anti-wear properties suitable for use in operations wherein high unit pressures are involved, said lubricant consisting essentially of about 2 to 5 Weight percent of di(2-etl1ylhexyl) lauroxyethylphosphonate and the balance being bis(2ethylhexyl)sebacate.

3. A lubricant composition having good extreme pressure and anti-wear properties suitable for use in applications wherein high unit pressures are involved, said lubri cant consisting essentially of about 2 to 5 weight percent 5 of diethyl oleoxybutyl phosphate and the balance being bis(2-ethylhexyl) sebacate.

References Cited in the file of this patent UNITED STATES PATENTS 10 2,285,853 Downing June 9, 1942 2,478,441 Wiley Aug 9, 1949 FOREIGN PATENTS 15 560,741 Great Britain July 22, 1958 OTHER REFERENCES Atkins et 211.: Development of Additives and Lubrieating Oil Compositions, I. and E. Chem, vol. 39, No. 20 4, April 1947, pp. 491-497. 

1. A LUBRICANT COMPOSITION HAVING GOOD EXTREME PRESSURE AND ANTI-WEAR PROPERTIES SUITABLE FOR USE IN SYSTEMS WHEREIN HIGH UNIT PRESSURES ARE INVOLVED, SAID LUBRICANT CONSISTING ESSENTIALLY OF ABOUT 2 TO 5 WEIGHT PERCENT OF DIBUTYL LAUROXYETHYLPHOSPHONATE AND THE BALANCE BEING BIS(2-ETHYLHEXYL)SEBACATE. 